The present invention relates to an apparatus for precisely measuring optical characteristics of an object to be examined, and to an optical characteristic measuring apparatus for allowing an observation of the object to be examined as well as for measuring the optical characteristics of the object to be examined. More particularly, when the object to be examined is a human eye, the present invention relates to an optical characteristic measuring apparatus which makes it possible to observe a front eye part of the eye to be examined as well as to measure optical characteristics of an irregular astigmatism component of the eye.
A conventional optical characteristic measuring apparatus for measuring the optical characteristics of the eye known as a refractometer is capable of expressing the optical characteristics of the eye merely as a spherical component, a regular astigmatism component and the angle of the axis of the regular astigmatism component.
Some eyes have an irregular astigmatism component in addition to a regular astigmatism component. Irregular astigmatism cannot be corrected by spectacles if the quantity of the irregular astigmatism component is large, contact lens must be used instead of a pair of spectacles lens, and the eye must be examined by a medical doctor.
A prior art apparatus for measuring the optical characteristics of the eye to be examined, however, could be used only for correcting eyeglasses, which was not so satisfactory.
Accordingly, desired strongly was an appearance of an optical characteristic measuring apparatus, which makes it possible to accurately measure the irregular astigmatism component of an object to be examined, to say nothing of a spherical component and a regular astigmatism component thereof and an axis angle of the regular astigmatism component, as well as makes it possible to observe the object to be examined with the use of only one light receiving device.